ADAM10- and presenilin 1/γ-secretase-dependent cleavage of PTPRT mitigates neurodegeneration of Alzheimer's disease

PTPRT (receptor-type tyrosine-protein phosphatase T), as a brain-specific type 1 transmembrane protein, plays an important function in neurodevelopment and synapse formation. However, whether PTPRT-dependent signaling is involved in Alzheimers disease (AD) remains elusive. Here, we identified that PTPRT intracellular domain (PICD), which was released from ADAM10- and presenilin 1-/{gamma}-secretase-dependent cleavage of PTPRT, efficiently translocated to the nucleus via a conserved nuclear localization signal. Inhibition of nuclear localization of PICD via the mutation of its nuclear localization signal (NLS) leads to accumulation of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), which is a substrate of PTPRT and eventually resulted in neuronal cell death. Consistently, RNA sequencing reveals that expression of the PICD alone can profoundly alter the expression of genes associated with synapse function and dephosphorylation, phosphatase and cell adhesion. Unexpectedly, the downregulated levels of Ptprt mRNA and protein were found in both human and mouse AD brains. Finally, overexpression of PICD alone not only significantly decreases the level of phosph-STAT3Y705 and A{beta} deposition in the hippocampus of APP/PS1 mice, but also improves synaptic function and behavioral deficits in APP/PS1 mice. Our findings suggest that a novel role of the ADAM 10- and presenilin 1-/{gamma}-secretase-dependent cleavage of PTPRT in the events can mitigate neurodegeneration of AD and moderate Alzheimers pathogenesis.